Since chlorine-containing propellants such as chlorofluorocarbons (CFCs) and hydrochlorofluorocarbons (HCFCs) cause ozone depletion in the upper atmosphere, tire inflator compositions containing CFC and HCFC propellants are being banned by the U.S. government and international bodies. Simple hydrocarbons such as propane, butanes, and their mixtures function as propellants in tire inflator compositions and do not destroy the ozone layer, but they are potentially dangerous to the customer and producer due to their flammability. Therefore, it is necessary to develop tire sealant and inflator compositions which use environmentally friendly, nonflammable propellants. Hydrofluorocarbons (HFCs) such as 1,1,1,2-tetrafluoroethane (HFC-134a) satisfy this criteria.
A number of prior art tire sealant and inflator compositions have been described. Abramowski et al. U.S. Pat. No. 5,142,395 discloses tire sealer and inflator compositions comprising a sealant, a propellant, a vapor pressure depressant, a freezing point depressant, a corrosion inhibitor, and a carrier.
Magyar et al. U.S. Pat. No. 4,501,825 discloses tire sealant and inflator compositions comprising a resin, a latex sealant, alkylene glycol, fibers, an alkanolamine, a foaming agent and water. The composition is packed in aerosol cans with a propellant/inflator and is used to seal and inflate punctured tires. The Magyar patent discloses examples of suitable resins including phenolic resins, such as phenol-formaldehyde resins and halogenated alkyl phenol resins, and derivatives of hydrogenated vegetable resins.
A recent Peelor et al. U.S. Pat. No. 5,338,776 discloses a tire sealant and inflator composition comprising an acrylic resin dissolved in a chlorinated solvent such as perchloroethylene.
There is no disclosure in each of the above patents that acetone, methyl ethyl ketone (MEK), acetonitrile, and tributyl phosphate are used as vapor pressure depressants for hydrofluorocarbon propellants such as HFC-134a in tire sealer and inflator compositions. Moreover, none of the patents discloses that petroleum residual resins and amorphous polyolefins are useful as sealants in tire sealer and inflator compositions.
The present invention provides new tire sealer and inflator compositions which represent an improvement over prior art compositions. The present tire sealant and inflator compositions are a substantial improvement over previous commercial tire sealant and inflator compositions for the following reasons: 1. They are nonflammable; 2. They do not use a CFC or HCFC propellant; 3. Formulations can be either aqueous or non-aqueous; and 4. They provide a superior sealing of tire puncture wounds. Other improvements that the present compositions offer over existing and previous formulas include a less or noncorrosive environment toward the can container, better long term chemical stability, and lower cost.